Remove SavePatch and generate patches on the fly (#9302)

* Save patches to temporary files

* Remove SavePatch and generate patches on the fly

* Use ioutil.TempDir

* fixup! Use ioutil.TempDir

* fixup! fixup! Use ioutil.TempDir

* RemoveAll LocalCopyPath() in initIntergrationTest

* Default to status checking on PR creation

* Remove unnecessary set to StatusChecking

* Protect against unable to load repo

* Handle conflicts

* Restore original conflict setting

* In TestPullRequests update status to StatusChecking before running TestPatch

models/pull_test.go

@@ -190,8 +190,6 @@ func TestPullRequest_UpdateCols(t *testing.T) {
 	CheckConsistencyFor(t, pr)
 }
 
-// TODO TestPullRequest_UpdatePatch
-
 // TODO TestPullRequest_PushToBaseRepo
 
 func TestPullRequestList_LoadAttributes(t *testing.T) {